利用采自长白山红松和落叶松分布上限和下限的树轮样本,分别建立树轮宽度差值年表。结果表明:下限红松年表的平均敏感度、树轮宽度指数的年际变率、信噪比等年表特征值比上限年表的高,表明下限红松生长对环境的敏感性大于上限;落叶松年表特征值在不同海拔表现与红松相反。进一步分析发现分布上限和下限的红松生长与气候因子之间的关系不同。下限红松生长与当年气温和上年降水显著相关,上限红松生长与当年气温显著相关,下限落叶松与上年气温显著相关,上限落叶松生长与当年气温和降水显著相关,降水随着海拔的升高而增加,过多的雨水伴随气温下降,进而限制落叶松生长,这表明落叶松生长的重要限制因子是气温,气温对下限落叶松生长产生滞后效应。
Tree-ring samples of Pinus koraiensis and Larix olgensis were studied along an altitudinal gradient on the northern slope of Changbai Mountains,Northeast China,and ring-width residual chronologies were developed for four sites at low and high elevations.Annual ring-width variability was different between elevation sites.For Pinus koraiensis,low elevation chronology had higher mean sensitivity(MS),standard deviation(SD) and signal-to-noise ratio(SNR),while high elevation chronology of Larix olgensis had higher mean sensitivity(MS),standard deviation(SD) and signal-to-noise ratio(SNR).Therefore,Pinus koraiensis growing at low elevation sites and Larix olgensis growing at high elevation sites had better climatic signals.Correlation analysis was used to study the relationships between tree-ring widths and mean monthly temperature and total monthly precipitation.The results showed that the growth of Pinus koraiensis at low elevations was affected by previous temperature and precipitation,and that at high elevations was only affected by temperature of current year.Temperature in the previous year played an important role in Larix olgensis' growth at low elevation sitea,while temperature and precipitation of current year made great contribution to Larix olgensis' growth at high elevation sites.With the increase of altitude precipitation increased,and more precipitation was related with low temperature.Consequently,tree growth was also affected by temperature with its indirect effect on the duration of growing season.Thus,the temperature was the most important factor influencing Larix olgensis,and showed that there was lag-effect of the growth response to climate force of low elevation.